Strongyle faecal egg counts in Swiss horses: A retrospective analysis after the introduction of a selective treatment strategy

The standard parasite management of horses based on regular anthelmintic treatments, now practiced for decades has resulted in a worrying expansion of resistant helminth populations, which may considerably impair control on the farm level. The aim of the present study was to obtain a retrospective (year 2010 - 2016) nationwide analysis of faecal egg count (FEC) data from the Swiss adult horse population, related to horse age and geographic region. Thirteen labs provided a total of 16,387 FEC data of horses aged four to 39 years (average: 13.6 years). The annual number of performed FEC tests increased from 38 to 4,939 within the observation period. Independent of the annual sample size the yearly patterns of the FEC were very similar. Seventy-eight percent (n = 12,840) of the samples were negative and 90 % (n = 14,720) showed a FEC below 200 strongyle eggs per gram (EPG) of faeces. The annual mean strongyle FEC ranged between 60 and 88 EPG with a total mean of 75 EPG. Horses aged 4-7 years showed a significantly (p < 0.00001) higher mean FEC compared with the other age groups, differences were not significant among the older horses. Based on ZIP codes, samples were allocated by 70.0 %, 6.0 % and 0.2 % to the German-, French- and Italian-speaking regions of Switzerland, respectively. With 222 EPG the mean FEC in the French part of Switzerland was significantly higher (p < 0.05) than in the German-speaking region (60 EPG). Eggs of Parascaris spp., anoplocephalids and Strongyloides westeri were found in 0.36 %, 0.32 % and 0.01 % of the samples, respectively. Based on 3,813 questionnaire feedbacks from owners in 2017 covering a total of 12,689 horses, sixty-eight percent (n = 8,476) were dewormed without diagnosis, two percent (n = 240) were not dewormed at all, whereas for 30 % (n = 3,721) the selective anthelmintic treatment (SAT) concept was applied. The SAT implementation rate differed significantly (p < 0.0005) between regions, with 33 %, 20 % and 25 % for the German-, French- and Italian-speaking areas, respectively. The rate of horses spending 16-24 h on pasture per day was significantly higher in the French-speaking region compared to the German-speaking part of Switzerland (p < 0.0001). In addition, pasture hygiene was practiced at a significantly lower rate in the French-speaking part compared to the German- and Italian-speaking regions (both p < 0.0001). Overall, the shift towards the SAT-concept represents a very promising development with respect to mitigating the further spread of anthelmintic resistance.

Social Box: A New Housing System Increases Social Interactions among Stallions

In domestic conditions, adult stallions are mostly housed individually in internal stables to reduce the risk of injuries during social interactions. Social deprivation in horses results in physiological stress and behavioural problems. The aim of this study was to test the "social box" (SB), which allows closer physical contact between neighbouring horses. Eight pairs of stallions (n = 16) were filmed over a 24 h period in the SB and in their usual box stables, "conventional boxes" (CB), which strongly restrict tactile contact. The effect of housing in the SB on behaviour and the occurrence and characteristics of injuries was investigated. The total duration of active social interactions was significantly higher in the SB than in the CB (51.1 vs. 4.9 min, p < 0.0001). Positive interactions accounted for about 71% of the total duration of interactions in SB and CB stabling. The stallions interacted significantly more often in the SB than in the CB (113.5 vs. 23.8 social interaction sequences over 24 h, p < 0.0001). No grievous injuries were recorded. The social box appears to be a suitable solution to give adult stallions the possibility of having physical interactions. Therefore, it can be considered a substantial environmental enrichment for singly housed horses.

Social Box: Influence of a New Housing System on the Social Interactions of Stallions When Driven in Pairs

In order to improve the housing conditions of stallions in individual boxes, we tested a so-called “social box” allowing increased physical contact between neighbouring horses. This study investigated whether housing stallions in social boxes changes the number of social interactions during carriage driving. We hypothesised that the stay in social boxes would decrease the number of unwanted social interactions between stallions when driven in pairs. Eight Franches-Montagnes breeding stallions were observed when driven in pairs with a “neutral” stallion housed in a so-called “conventional box”, strongly limiting physical contact. They were driven on a standardised route over the course of four days before, during, and after being housed in social boxes. The type and frequency of behaviours of the pairs and the interventions of the groom and the driver during the test drives were assessed live and using video recordings. Results from linear mixed-effect models show that unwanted social interactions decreased during and after the stallions were housed in the social box (p < 0.001). Stallions’ interactions also decreased over the four days (p < 0.01), suggesting a habituation to the test conditions by learning not to interact, or by subtly settling dominance. The social box tended to decrease unwanted social behaviours of stallions driven in pairs and could therefore be used as an environmental enrichment for horses.

Thrombelastography in the surgical patient

Coagulopathy in surgical patients is an important factor in triggering major perioperative complications, i.e., intra- or postoperative bleeding and thrombo-embolic events associated with an increased mortality and morbidity. Different methods exist to assess the coagulation status of patients before, during and after surgery. Routine coagulation tests have long been considered to be the clinical standard. However, these tests have considerable limitations. Information regarding the kinetics of clot formation, clot strength, interaction of the coagulation components, platelet function and fibrinolysis is not available. Moreover, there is an important delay in obtaining test results. In contrast, thrombelastography and thrombelastometry, which both measure the visco-elastic properties of whole blood, allow the dynamic assessment of a developing clot, from fibrin formation to clot strengthening and clot lysis. Both techniques are increasingly being used in daily clinical practice in order to detect perioperative coagulopathy and to guide predominantly pro-coagulant therapy in different settings. This article provides an overview of both techniques, thrombelastography (TEG) and thrombelastometry (ROTEM), and their field of perioperative application considering of recently published data.

High dose N-acetylcysteine to prevent pulmonary complications in partial or total transthoracic esophagectomy: results of a prospective observational study

Cancer of the esophagus has a poor long-term prognosis and a high peri-operative morbidity in which pulmonary complications play a major role. The combination of the surgical approach, pre-existing pulmonary disorders, poor nutritional status and the release of pro-inflammatory cytokines may be contributing factors. N-acetylcysteine ((NAC) has been shown to have oxygen scavenging abilities. In severe sepsis and acute respiratory distress syndrome, positive effects of NAC on morbidity and mortality were discovered. In this observational study peri-operative high dose NAC was administered in 22 patients. The effects of this treatment on respiratory function, morbidity and survival were studied. These prospectively collected data were compared with data of a matched, retrospective group without NAC treatment. There were no significant differences between the groups in terms of socio-demographic data, preoperative pulmonary function, intra-operative course and oncologic characteristics. The oxygenation indices at the postoperative hours 2 (P = 0.019), 4 (P < 0.001), 8 (P = 0.035), 12 (P = 0.035) and 24 (P = 0.046) were significantly higher in the NAC group. After 36 h, the difference between groups was no longer significant (P = 0.064). NAC-treated patients showed significant lower overall pulmonary morbidity, 45.5% versus 81.8% (P = 0.027). Surgical morbidity, intensive care unit and hospital stay were not significantly different between groups, mortality was zero. Kaplan-Meier curves showed no significant difference in survival 12 months postoperatively. These data indicate that postoperative oxygenation can be improved and rate of overall pulmonary complications is reduced using peri-operative high dose NAC in transthoracic esophagectomy.

Clinical evaluation of the FloTrac/Vigileo system and two established continuous cardiac output monitoring devices in patients undergoing cardiac surgery

BACKGROUND

Assessment of cardiac output (CO) by the FloTrac/Vigileo system may offer a less invasive means of determining the CO than either the pulmonary artery catheter (PAC) or the PiCCOplus system. The aim of this study was to compare CO measurements made using the FloTrac/Vigileo system with upgraded software (FCO, Edwards Lifesciences, Irvine CA, USA), the PiCCOplus system (PCO, Pulsion Medical Systems, Munich, Germany) and continuous CO monitoring using a PAC (CCO; Vigilance monitoring, Edwards Lifesciences, Irvine CA, USA) with intermittent pulmonary artery thermodilution (ICO). The study was conducted in patients undergoing elective cardiac surgery.

METHODS

Thirty-one patients with preserved left ventricular function were enrolled. CCO, FCO, and PCO were recorded in the perioperative period at six predefined time points after achieving stable haemodynamic conditions; ICO was determined from the mean of three bolus injections. Bland-Altman analysis was used to compare CCO, FCO, and PCO with ICO.

RESULTS

Bland-Altman analysis revealed a comparable mean bias and limits of agreement for all tested continuous CO monitoring devices using ICO as reference method. Agreement for all devices decreased in the postoperative period.

CONCLUSION

The performance of the FloTrac/Vigileo system, the PiCCOplus, and the Vigilance CCO monitoring for CO measurement were comparable when tested against intermittent thermodilution in patients undergoing elective cardiac surgery.

Anaesthesia for lung volume reduction surgery

To date, only a few published studies have been concerned with the anaesthesiological aspects of lung volume reduction surgery. This review summarizes the different anaesthetic concepts and offers a general strategy to meet specific requirements. Limitation of peak inspiratory pressure, tolerance of hypercapnia and avoidance of hypoxia during one-lung ventilation, and the immediate postoperative tracheal extubation of these patients, are considered to be crucial. However, many aspects of the procedure and of anaesthesiological management remain to be elucidated.

Präoperative Nüchternzeiten

BACKGROUND

In order to improve perioperative subjective quality of care it seems desirable to shorten preoperative fasting times as much as possible within acceptable safety limits. These efforts should result in a measurable reduction of preoperative thirst and hunger as well as in improvements of patient well-being. It is unknown to what extent preoperative patient comfort is limited by thirst and hunger from a patient point of view. The purpose of this study was to determine the impact of a traditional fasting regimen on preoperative patient discomfort.

PATIENTS AND METHODS

We conducted a survey on preoperative thirst and hunger in 412 adult American Society of Anesthesiologists ASA I and II patients scheduled for minor elective surgery.

RESULTS

Of the patients 33% complained of moderate to strong thirst, whereas 19% had moderate to strong hunger, 47% of the participants would have liked to have been able to drink and 72% would have appreciated a light breakfast before surgery. Mean preoperative fasting times were 12.8+/-3.4 h for fluids and 15.5+/-4.4 h for solids. "Thirst" was named by 3.3% and "hunger" by 0.8% of patients as the most important factor for preoperative discomfort but "long wait" (8.5%), "tenseness" (6.5%) and "anxiety" (4.8%) were the most frequently named factors. Answers were independent of the duration of preoperative fasting.

CONCLUSION

Patient comfort is compromised by traditional fasting rules and liberalization of these policies is desired by patients. However, efforts to reduce preoperative anxiety and tenseness might have an additional, important potential to improve perioperative quality of care from a patient's perspective.

Volumetric assessment of left heart preload by thermodilution: comparing the PiCCO-VoLEF system with transoesophageal echocardiography

The new Volumetric Ejection Fraction monitoring system (VoLEF), when combined with the Pulse Contour Cardiac Output monitoring system (PiCCO) system, allows measurement of left and right heart end-diastolic volumes by thermodilution. The aim of this study was to evaluate whether the left heart end-diastolic volume index determined by the VoLEF system (LHEDI) better reflects left ventricular end-diastolic area index (LVEDAI) measured by transoesophageal echocardiography than does global end-diastolic volume index (GEDI) measured by the PiCCO system alone. Following induction of anaesthesia, PiCCO, VoLEF and transoesophageal echocardiography measurements were performed before and after a fluid challenge in 20 patients scheduled for elective cardiac surgery. Both left ventricular end-diastolic area index and global end-diastolic volume index, but not left heart end-diastolic volume index, significantly increased after fluid administration. Mean bias +/- 2 SD for DeltaLHEDI-DeltaLVEDAI was -2.2 +/- 32.0% and for DeltaGEDI-DeltaLVEDAI -0.6 +/- 16.8%. In contrast to global end-diastolic volume index, the use of left heart end-diastolic volume index determined by the VoLEF system cannot be recommended as an estimate of left ventricular preload.

Effects of heparin, haemodilution and aprotinin on kaolin-based activated clotting time: in vitro comparison of two different point of care devices

BACKGROUND

During cardiopulmonary bypass (CPB), measurement of kaolin-based activated clotting time (kACT) is a standard practice in monitoring heparin-induced anticoagulation. Despite the fact that the kACT test from the Sonoclot Analyzer (SkACT) has been commercially available for several years, no published data on the performance of SkACT are available. Thus, the aim of this in vitro study was to compare SkACT with an established kACT from Hemochron (HkACT).

METHODS

Blood was withdrawn from 25 patients before elective cardiac surgery. SkACT and HkACT were measured in duplicate after in vitro administration of heparin (0, 1, 2 and 3 U/ml), calcium-free lactated Ringer's solution (25% and 50% haemodilution) and aprotinin (200 kIU/ml).

RESULTS

A total of 600 duplicate kACT measurements were obtained from 25 cardiac surgery patients. Overall, mean bias +/- SD between SkACT and HkACT was 7 +/- 70 s (1.3% +/- 14.1%). Administration of heparin, haemodilution and aprotinin induced a comparable effect on both activated clotting time (ACT) tests. Mean bias ranged from -4 +/- 39 s (-1.7% +/- 12.9%) to 4 +/- 78 s (3.2% +/- 15.6%) for heparinzed blood samples after haemodilution or aprotinin application and increased after combined aprotinin administration and haemodilution. After haemodilution and administration of aprotinin, both ACT tests were less reliable for values >480 s in heparinized blood samples.

CONCLUSION

Accuracy and performance of SkACT and HkACT were comparable after in vitro administration of heparin, aprotinin and haemodilution. Both ACT tests were considerably affected by aprotinin and haemodilution.

Influence of body core temperature on blood loss and transfusion requirements during off-pump coronary artery bypass grafting: a comparison of 3 warming systems

BACKGROUND

The aim of this prospective randomized trial was to evaluate the efficacy of 3 intraoperative warming systems (Warm-Touch, Thermamed SmartCare OP system, and Allon 2001) on maintenance of normothermia and to investigate their effects on perioperative bleeding and transfusion requirements in patients undergoing off-pump coronary artery bypass grafting.

METHODS

With institutional approval/patient informed consent, 90 patients presenting for elective multiple off-pump coronary artery bypass grafting were randomly assigned to 1 of the 3 warming systems. Active warming was started after the induction of anesthesia. Perioperative transfusion was based on international guidelines. Body core temperature was recorded every 30 minutes during operation. Perioperative blood loss, autotransfusion, and allogenic transfusions were recorded. Analysis of variance was performed with post hoc Scheffé tests and chi 2 tests.

RESULTS

Normothermia could be sufficiently maintained during operation by the Allon 2001 only. Final body core temperature was 34.7 degrees C +/- 0.9 degrees C (Warm-Touch), 35.6 degrees C +/- 0.8 degrees C (Thermamed SmartCare OP), and 36.5 degrees C +/- 0.4 degrees C (Allon 2001; P < .001, Warm-Touch vs Thermamed SmartCare OP, Warm-Touch vs Allon 2001, and Thermamed SmartCare OP vs Allon 2001). Perioperative blood loss was 2683 +/- 1049 mL (Warm-Touch), 2300 +/- 788 mL (Thermamed SmartCare OP), and 1497 +/- 497 mL (Allon 2001; P = .195, Warm-Touch vs Thermamed SmartCare OP; P < .001, Warm-Touch vs Allon 2001; P = .001, Thermamed SmartCare OP vs Allon 2001). Transfusion requirements were 1097 +/- 874 mL (Warm-Touch), 986 +/- 744 mL (Thermamed SmartCare OP), and 431 +/- 387 mL (Allon 2001; P = .838, Warm-Touch vs Thermamed SmartCare OP; P = .003, Warm-Touch vs Allon 2001; P = .013, Thermamed SmartCare OP vs Allon 2001). Free of allogenic transfusion were 15 (51.7%; Warm-Touch), 18 (60%; Thermamed SmartCare OP), and 24 (82.8%; Allon 2001) patients ( P = .037).

CONCLUSIONS

The goal of normothermia during off-pump coronary artery bypass grafting was best achieved by the Allon system. With this concept, overall blood loss and transfusion requirements were reduced, hence indicating improved quality of perioperative care.

Volumetric preload measurement by thermodilution: a comparison with transoesophageal echocardiography

BACKGROUND

End-diastolic volume indices determined by transpulmonary thermodilution and pulmonary artery thermodilution may give a better estimate of left ventricular preload than pulmonary capillary wedge pressure monitoring. The aim of this study was to compare volume preload monitoring using the two different thermodilution techniques with left ventricular preload assessment by transoesophageal echocardiography (TOE).

METHODS

Twenty patients undergoing elective cardiac surgery with preserved left-right ventricular function were studied after induction of anaesthesia. Conventional haemodynamic variables, global end-diastolic volume index using the pulse contour cardiac output (PiCCO) system (GEDVI(PiCCO)), continuous end-diastolic volume index (CEDVI(PAC)) measured by a modified pulmonary artery catheter (PAC), left ventricular end-diastolic area index (LVEDAI) using TOE and stroke volume indices (SVI) were recorded before and 20 and 40 min after fluid replacement therapy. Analysis of variance (Bonferroni-Dunn), Bland-Altman analysis and linear regression were performed.

RESULTS

GEDVI(PiCCO), CEDVI(PAC), LVEDAI and SVI(PiCCO/PAC) increased significantly after fluid load (P<0.05). An increase >10% for GEDVI(PiCCO) and LVEDAI was observed in 85% and 90% of the patients compared with 45% for CEDVI(PAC). Mean bias (2 SD) between percentage changes (delta) in GEDVI(PiCCO) and deltaLVEDAI was -3.2 (17.6)% and between deltaCEDVI(PAC) and deltaLVEDAI -8.7 (30.0)%. The correlation coefficient (r2) for deltaGEDVI(PiCCO) vs deltaLVEDAI was 0.658 and for deltaCEDVI(PAC) vs deltaLVEDAI 0.161. The relationship between deltaGEDVI(PiCCO) and deltaSVI(PiCCO) was stronger (r2=0.576) than that between deltaCEDVI(PAC) and deltaSVI(PAC) (r2=0.267).

CONCLUSION

GEDVI assessed by the PiCCO system gives a better reflection of echocardiographic changes in left ventricular preload, in response to fluid replacement therapy, than CEDVI measured by a modified PAC.

Preconditioning with sevoflurane decreases PECAM-1 expression and improves one-year cardiovascular outcome in coronary artery bypass graft surgery

BACKGROUND

Cardiac preconditioning is thought to be involved in the observed decreased coronary artery reocclusion rate in patients with angina preceding myocardial infarction. We prospectively examined whether preconditioning by sevoflurane would decrease late cardiac events in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

Seventy-two patients scheduled for elective CABG surgery were randomized to preconditioning by sevoflurane (10 min at 4 vol%) or placebo. For all patients, follow-up of adverse cardiac events was obtained 6 and 12 months after surgery. Transcript levels for platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31), catalase and heat shock protein 70 (Hsp70) were determined in atrial biopsies after sevoflurane preconditioning.

RESULTS

Pharmacological preconditioning by sevoflurane reduced the incidence of late cardiac events during the first year after CABG surgery (sevoflurane 3% vs 17% in the placebo group, log-rank test, P=0.038). One patient in the sevoflurane group and three patients in the placebo group experienced new episodes of congestive heart failure and three additional patients had coronary artery reocclusion. Perioperative peak concentrations for myocardial injury markers were higher in patients with subsequent late cardiac events [NTproBNP, 9031 (4125) vs 3049 (1906) ng litre(-1), P<0.001; cTnT, 1.31 (0.88) vs 0.46 (0.29) microg litre(-1), P<0.001]. Transcript levels were reduced for PECAM-1 and increased for catalase but unchanged for Hsp70 in atrial biopsies after sevoflurane preconditioning.

CONCLUSIONS

This prospective randomized clinical study provides evidence of a protective role for pharmacological preconditioning by sevoflurane in late cardiac events in CABG patients, which may be related to favourable transcriptional changes in pro- and antiprotective proteins.

Welche Bed�rfnisse und Erwartungen haben Patienten an die An�sthesie?

BACKGROUND

This prospective survey aimed at elucidating the patients' expectations and needs regarding the pre-anaesthetic visit and the forthcoming anaesthesia. The same questionnaire was answered by both patients and anaesthesiologists.

METHODS

A total of 200 ASA I-III patients were interviewed prior to the preoperative anaesthetic visit. The questionnaire consisted of the topics preoperative affective situation, information and self-estimation of anaesthesia knowledge, expectations regarding the pre-anaesthetic visit/anaesthesia and extent of information concerning the perioperative course including risk and possible complications. The same questionnaire was presented to 35 certified anaesthesiologists with the request to estimate the patients' answers. Answers were rated using a Likert-scale, a comparison of patients' and anaesthesiologists' replies was performed.

RESULTS

For all 5 topics considerable differences between patients' answers and anaesthesiologists' rating were found (e.g. for the assessment of the affective situation, the relevance of family physicians as information source, the desired anaesthetic technique or the extent of anaesthesia-related risk information). No differences were observed for the importance of an anaesthesiologist as information source and fear reduction by the pre-anaesthetic visit.

CONCLUSIONS

Anaesthesiologists tend to misinterpret many patients' expectations and attitudes. The results demonstrate the potential for quality improvement of the pre-anaesthetic visit.

Pulsed dye densitometry with two different sensor types for cardiac output measurement after cardiac surgery: a comparison with the thermodilution technique

BACKGROUND

Assessment of cardiac output (CO) by the indocyanine green (ICG) dye dilution technique (IDD) with transcutaneous signal detection may be a less invasive alternative to the pulmonary artery catheter (PAC). The aim of this study was to determine the accuracy and reliability of the DDG2001 analyzer (Nihon Kohden Corp, Tokyo, Japan) using a finger (IDDf) and a nose (IDDn) sensor as compared with the thermodilution technique by PAC.

METHODS

In 31 consecutive patients after routine cardiac surgery, CO measurements were performed by IDD compared with the thermodilution technique following postoperative haemodynamic stabilization in the intensive care unit. Repeated measurements were made at 30-min intervals. CO was determined by iced water bolus (IWB: mean of three repeated injections) and IDDf or IDDn, respectively (mean of three repeated ICG injections).

RESULTS

Thirty-three per cent of all measurements for IDDf and 9% for IDDn failed due to a missing signal detection. Mean bias for IDDf to IWB was -0.5 l min(-1).m(-2) (limits of agreement: -1.8/0.8 l min(-1).m(-2)) and for IDDn to IWB was -0.1 l min(-1).m(-2) (limits of agreement: -1.6/1.5 l min(-1).m(-2)). Correlation between IDDf and IWB (r = 0.2) was found to be inferior to the correlation between IDDn and IWB (r = 0.5).

CONCLUSION

The IDD showed a systematic bias compared with the IWB and its performance was limited due to signal detection failure. Therefore, the DDG2001 analyzer cannot be recommended as a substitute for the PAC in routine monitoring of cardiac output after cardiac surgery.

Therapeutic impact of intra-operative transoesophageal echocardiography during noncardiac surgery

The impact of transoesophageal echocardiography on haemodynamic management during elective noncardiac surgery was assessed during this observational prospective database analysis. Ninety-nine consecutive patients were studied, who were at risk of intra-operative myocardial ischaemia or haemodynamic instability (Class II indications) and were undergoing vascular, visceral or chest surgery. A total of 165 new echocardiographic findings were recorded. Based on these findings changes in drug therapy were made in 47% and changes in fluid therapy in 24% of patients. Left ventricular wall motion abnormalities were seen in 32% and other relevant diagnoses made in 10%. Echocardiography showed a significant impact on drug therapy in patients with pre-operative systolic wall motion abnormalities (vasodilators: OR = 7.1, CI 95% = 2.1/24.0; vasopressors: OR = 3.3, CI 95% = 1.2/9.1) and patients with a history of left heart failure (vasodilators: OR = 5.2, CI 95% = 1.0/31.4). Fluid therapy was significantly influenced by echocardiographic findings during liver and lung transplantation (50% compared with 24% during other surgical interventions, p < 0.05).

Patient well-being after general anaesthesia: a prospective, randomized, controlled multi-centre trial comparing intravenous and inhalation anaesthesia

BACKGROUND

The aim of this study was to assess postoperative patient well-being after total i.v. anaesthesia compared with inhalation anaesthesia by means of validated psychometric tests.

METHODS

With ethics committee approval, 305 patients undergoing minor elective gynaecologic or orthopaedic interventions were assigned randomly to total i.v. anaesthesia using propofol or inhalation anaesthesia using sevoflurane. The primary outcome measurement was the actual mental state 90 min and 24 h after anaesthesia assessed by a blinded observer using the Adjective Mood Scale (AMS) and the State-Trait-Anxiety Inventory (STAI). Incidence of postoperative nausea and vomiting (PONV) and postoperative pain level were determined by Visual Analogue Scale (VAS) 90 min and 24 h after anaesthesia (secondary outcome measurements). Patient satisfaction was evaluated using a VAS 24 h after anaesthesia.

RESULTS

The AMS and STAI scores were significantly better 90 min after total i.v. anaesthesia compared with inhalation anaesthesia (P=0.02, P=0.05, respectively), but equal 24 h after both anaesthetic techniques (P=0.90, P=0.78, respectively); patient satisfaction was comparable (P=0.26). Postoperative pain was comparable in both groups 90 min and 24 h after anaesthesia (P=0.11, P=0.12, respectively). The incidence of postoperative nausea was reduced after total i.v. compared with inhalation anaesthesia at 90 min (7 vs 35%, P<0.001), and 24 h (33 vs 52%, P=0.001).

CONCLUSION

Total i.v. anaesthesia improves early postoperative patient well-being and reduces the incidence of PONV.

Continuous intravascular blood gas monitoring: development, current techniques, and clinical use of a commercial device

This review focuses on the development, current techniques, and clinical use of continuous intravascular blood gas monitoring (CIBM) devices in anaesthesia and intensive care. The operating principles, range of application, performance, limitations, costs, and impact on patient treatment and outcome, are discussed. Studies of early and currently available CIBM devices were analysed. At present, the Paratrend 7+ (PT7+) for adults and Neotrend (NT) for newborns are the only commercially available CIBM systems. The PT7+ contains three optical sensors to measure PO(2), PCO(2) and pH, as well as a thermocouple to measure temperature. The NT is a modification of the PT7+ to continuously monitor PO(2), PCO(2), pH and temperature in newborns. Under laboratory conditions, good performance over a wide range of blood gas values was observed with the Paratrend 7 (PT7. Performance in the clinical setting was not as satisfactory, especially for PO(2) values. However, the performance and accuracy of CIBM devices appear to be sufficient for clinical use and they are being used clinically in selected patient groups. Several factors affecting the performance of CIBM are considered.

[Complete heart block after spinal and general anaesthesia]

Complete atrioventricular block occurred during spinal and subsequent general anaesthesia in a 74-year-old patient with known arterial hypertension but without heart conduction abnormality. Drug therapy and intermittent transcutaneous pacing was successful. A decrease of arterial pressure by more than 40% preceded the heart blockade in the course of both events. Subsequent cardiologic examination revealed evidence of a discrete hypertensive heart disease. Relative ischemia of the atrioventricular region during anaesthesia was suggested as an aetiology. When the patient presented for the next operation, again general anaesthesia was applied, and invasive arterial blood pressure monitoring as well as catecholamine support were used and no further atrioventricular blockade occurred. The case demonstrates the possible recurrence of an intraoperative complete atrioventricular blockade in an older patient without pre-existing conduction abnormalities and only minor signs of heart disease, irrespective of the anaesthesia technique. Under these circumstances transcutaneous pacing should always be in place. Maintenance of coronary perfusion pressure is essential and invasive blood pressure monitoring is recommended.

Profound drug-induced thrombocytopenia before urgent cardiopulmonary bypass

A patient with acute coronary syndrome scheduled for urgent coronary artery bypass grafting developed a profound thrombocytopenia during therapy with intravenous heparin and the glycoprotein IIb/IIIa inhibitor tirofiban. Heparin-induced thrombocytopenia and all other possible aetiologies were unlikely and the low platelet count had to be attributed to tirofiban. Anticoagulation during cardiopulmonary bypass was successfully managed with standard heparin. Implications for the diagnosis of coagulation disorders and the management of perioperative anticoagulation are discussed.

Changes in intrathoracic blood volume associated with pneumoperitoneum and positioning

BACKGROUND

It is still controversial whether elevated cardiac filling pressures after the onset of pneumoperitoneum are the consequence of increased intrathoracic pressure or of increased venous return. The aim of this study was to assess the effects of pneumoperitoneum and body positioning on intrathoracic blood volume (ITBV).

METHODS

Thirty anesthetized patients were randomly assigned to have CO2-pneumoperitoneum (13 mmHg) either in a supine, in a 15 degrees head-up tilt or in a 15 degrees head-down tilt position. Measurements of ITBV and hemodynamics by the double indicator method were recorded after induction of anesthesia and application of a fluid bolus (Lactated Ringer's solution 10 ml/kg), after positioning and after induction of pneumoperitoneum.

RESULTS

Intrathoracic blood volume index (ITBVI) increased significantly after induction of pneumoperitoneum in all body positions (supine: from 18.5 +/- 3.3 -20.2 +/- 5.2 ml/kg (+6%) head-up from 16.7 +/- 3.8 - 17.4 +/- 3.7 ml/kg (+16%) and head-down: from 19.8 +/- 5.6 - 20.5 +/- 5.9 ml/kg (+14%)). Heart rate did not change significantly in any of the groups. Cardiac index showed a statistically significant change in the head-down position with pneumoperitoneum (-11%). A good correlation was found for stroke volume (SV) with ITBV (r = 0.79), but not with central venous pressure (r = 0.26). Systemic vascular resistance index increased significantly in all three groups (supine +6%, head-up +16%, head-down position +14%).

CONCLUSION

The present study indicates that the onset of pneumoperitoneum, even with moderate intra-abdominal pressures, is associated with an increased intrathoracic blood volume in ASA I/II patients.

[Participation--oriented analysis of the anesthesia workplace. A work system for anesthesia in a multidisciplinary operating room]

INTRODUCTION

The aim of this study was the detection and understanding of weak points in the ergonomic design of anaesthesia workplaces in a multidisciplinary operating room facility.

METHODS

Analysis of workplaces and of working processes by means of observations, computer-supported task recording and video-photo documentation. During guided interviews the participants were provided with material for naming-by-pointing and drawing. Subsequently, the background of the problems encountered and possible improvements were visualised.

RESULTS

Important deficits were devices not positioned within reach and view, difficulties in operating the lines connecting the patient and the devices, and inconsistent workplace layouts. These were caused by erroneous planning of the facility and disregarding ergonomic principles in equipment design. The initial improvements implemented were the development of a new concept for a flexible equipment positioning and the design of a tool for cable handling.

DISCUSSION AND CONCLUSION

Although from the very beginning of the study the anaesthesia personnel quoted the handling of the lines connecting patients and devices as the main cause for working difficulties, the external ergonomist could contribute to a broader view of the problems. The method presented here initiated a mutual learning process between ergonomist and users and resulted in a common understanding of the problems and their causes. Compared to the traditional consulting process, more time and efforts were necessary but were offset by the users' acceptance of the improvements and the prevention of design errors.

How reliable is length-based determination of body weight and tracheal tube size in the paediatric age group? The Broselow tape reconsidered

BACKGROUND

The Broselow tape was designed to estimate body weight and tracheal tube size on the basis of the body length of emergency paediatric patients. The tape was validated previously in US populations. We assessed its accuracy in a sample of European children by reviewing paediatric anaesthetic charts at the Triemli City Hospital for 1999.

METHODS

Age, body length and body weight measured before surgery as well as the size of the tracheal tube used were recorded. The body weight was estimated on the basis of body length using the Broselow tape and was compared with the measured weight. Tracheal tube size selections using the Broselow tape and an age-based formula were compared with the size of the tube used.

RESULTS

A good correlation was found between the Broselow weight and the measured weight (r2=0.88). Bland-Altman analysis revealed a mean bias of -0.52 kg for the entire study population. For children < or = 20 kg the mean bias was -0.05 kg, and for children > 20 kg was -1.05 kg. The Broselow weight was found to be within a 10% error of the measured weight in 65% of children. Tracheal tube selection by the Broselow tape method was adequate in 55% but underestimated the actual tube size in 39%. The age-based formula matched the actual tracheal tube size in 41% of children but overestimated it in 57%.

CONCLUSIONS

The Broselow tape is an accurate means to assess body weight from length in smaller children; in older children it underestimated body weight. Endotracheal tube size selection by the Broselow tape appears to match the size of the tube used better than the age-based formula. The results in a European sample of children are comparable to the US data.

Total intravenous anaesthesia in a patient with familial hypokalaemic periodic paralysis

A 35-year-old woman with known familial hypokalaemic periodic paralysis received general anaesthesia for reduction of bilateral breast hyperplasia. Uncomplicated general anaesthesia was performed using a propofol target-controlled infusion, remifentanil infusion and bolus doses of mivacurium with neuromuscular function monitoring. Plasma potassium concentrations were controlled intermittently in the peri-operative period and supplemented to achieve normokalaemia. Despite continuous substitution, an episode of low plasma potassium concentration occurred during the recovery period; this was without any clinical signs of muscle paralysis or respiratory distress.

[The NACA scale. Construct and predictive validity of the NACA scale for prehospital severity rating in trauma patients]

The NACA-scale is used in many Austrian, German and Swiss emergency medical systems for demographic description of emergency patients. Little attention has been payed to the evaluation of its construct and predictive validity. In 427 consecutive trauma patients rescued in primary mission the NACA-Scale and the Injury Severity Score (ISS) were determined. Outcome data were obtained from medical charts and by written or telephone requests. Data were analysed with Spearman-Rank-Correlation. NACA-Grade and ISS-values showed only a moderate correlation with a considerably large spread (Rho = 0.721). Both severity scores demonstrated a good correlation to mortality (Rho = 0.976/0.994) and to transfer to an ICU (Rho = 0.964/0.943), as well a moderate correlation to the duration of ICU-stay (Rho = 0.722/0.756) and of hospital stay (Rho = 0.558/0.694). The NACA-scale adequately describes life threat in trauma victims and correlates well with morbidity and mortality. Thus, it is a valuable tool for demographic purposes in emergency medical systems. For more precise prehospital severity rating in trauma patients, the NACA-scale should be supplemented or replaced by a physiologically based prehospital severity score.

Preoperative pulmonary evaluation: facts and myths

This review summarizes recent reports on preoperative pulmonary evaluation focusing on the impact on outcome in thoracic and non-thoracic surgery. Data suggest that hitherto widely accepted pulmonary function tests do not predict perioperative complications. Therefore, they may not be considered alone to decide on the patient's operability. So-called prohibitive lung function parameters should no longer be used to deny a potentially curative lung resection. A more clinically oriented, interdisciplinary approach to severely compromised patients may be best suited to discuss and solve their problems.

[Cardiovascular stress protection following anesthesia induction. Comparison of clonidine and esmolol]

Alpha-2-adrenoceptor-agonists as well as cardioselective betareceptor-antagonists have been shown to blunt stress response due to tracheal intubation. The purpose of our study was to investigate,whether clonidine or esmolol is more efficient to attenuate stress response due to intubation.44 patients were randomly assigned to receive either clonidine (n=22; 3 microg/kg) or esmolol (n=22; 2 mg/kg) immediately prior to a standardized induction of anaesthesia. Heart rate, arterial blood pressure, cardiac output, epinephrine and norepinephrine plasma concentrations were measured before,during and 10 min after intubation. Blood pressure was measured invasively and cardiac output was determined by transthoracic echocardiography. Absolute values and increase of mean arterial pressure and norepinephrine plasma concentrations were significantly less in the clonidine group (p<0,05). Clonidine (3 microg/kg) is more efficient than esmolol (2 mg/kg) in blunting stress response due to endotracheal intubation.

Low- and medium-molecular-weight hydroxyethyl starches: comparison of their effect on blood coagulation

BACKGROUND

High-molecular-weight hydroxyethyl starch (HES) compromises blood coagulation more than medium-molecular-weight HES. The authors compared medium molecular weight HES (200 kd [HES200]) and low-molecular-weight HES (70 kd [HES70]).

METHODS

In a prospective, double-blind, randomized-sequence crossover study, 22 male volunteers received 15 ml/kg HES200 and HES70. Blood samples were taken before and 5 min, 30 min, 1 h, 2 h, 4 h, 8 h, and 24 h after infusion. The following parameters were analyzed at all time points: prothrombin time, activated partial thromboplastin time, fibrinogen, factor VIII, antigenetic and functional von Willebrand factor, platelets, Thrombelastograph analysis parameters (reaction time, coagulation time, maximum amplitude, angle alpha, and clot lysis 30 and 60 min after maximum amplitude), ionized calcium, hematocrit, HES plasma concentration, molecular weight (weight average and number average), molar substitution, and polydispersity (weight average/number average). Repeated-measures analysis of variance (P < 0.05) was used to compare the response of the aforementioned parameters to the infusion of HES70 and HES200.

RESULTS

Both HES solutions had a significant impact on all parameters. A slightly greater compromise with HES200 was found in activated partial thromboplastin time (P = 0.010), factor VIII (P = 0.009), antigenetic von Willebrand factor (P = 0.041), functional von Willebrand factor (P = 0.026), maximum amplitude (P = 0.008), and angle alpha (P = 0.003). No difference was established with the other parameters. HES concentration (P < 0.001), weight average (P < 0.001), number average (P < 0.001), and polydispersity (P < 0.001) were higher with HES200. There was no difference with molar substitution (P = 0.091).

CONCLUSIONS

Low-molecular-weight hydroxyethyl starch (70 kd) compromises blood coagulation slightly less than HES200, but it is unclear whether this is clinically relevant.

Interleukin-10 secretion by alveolar macrophages and monocytes in sarcoidosis

BACKGROUND

Alveolitis and the production of proinflammatory cytokines are known features of sarcoidosis. Because of the usually spontaneous resolution of alveolitis despite local secretion of mediators causing inflammation and granuloma formation, we hypothesized that downmodulating mechanisms such as anti-inflammatory cytokines might be involved in this process.

OBJECTIVE

Investigation of the secretion of the macrophage deactivating cytokines interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) by alveolar macrophages in untreated sarcoidosis of the lung.

METHODS

Fourteen consecutive and untreated patients with pulmonary sarcoidosis and 18 volunteers underwent bronchoscopy. Alveolar macrophages (AM) were obtained by bronchoalveolar lavage and the secretion of IL-10 and TGF-beta was studied.

RESULTS

Spontaneous IL-10 production by AM was found in 6 of 14 patients and in 2 of 18 controls. The IL-10 level of lipopolysaccharide-stimulated AM was significantly higher in patients. Monocytes secreted significantly more IL-10 than AM, but there was no difference between sarcoid and control monocytes. No difference was found in the secretion of TGF-beta between patients and controls.

CONCLUSION

Increased local secretion of IL-10 - but not TGF-beta - may represent a downmodulating mechanism involved in the spontaneous resolution of alveolitis in sarcoidosis.

Preoperative clonidine attenuates stress response during emergence from anesthesia

STUDY OBJECTIVES

To investigate whether a single preoperative IV dose of clonidine blunts the hemodynamic and hyperadrenergic responses not only to intubation, but also to extubation.

DESIGN

Randomized, double-blind, placebo-controlled study.

PATIENTS

29 ASA physical status I and II patients (ages 18-65) who were scheduled for noncardiac, elective surgery. Patients were randomly assigned to either receive clonidine 3 microg/kg IV immediately before anesthesia induction or placebo.

INTERVENTIONS

Insertion of a 14 G cannula in a large cubital vein for the determination of plasma catecholamines using local anesthesia. Insertion of a radial artery catheter for measuring blood pressure (BP) using local anesthesia. Transthoracic echocardiography to determine cardiac output (CO).

MEASUREMENTS

Heart rate (HR), mean arterial pressure (MAP), CO, and plasma catecholamine concentrations. Measurements were performed: before induction (baseline), during intubation, 10 min after intubation, after surgery, during extubation, and 10 min after extubation.

MAIN RESULTS

During intubation MAP, HR, and CO were lower in the clonidine group. Compared with baseline measurements, MAP and CO increased less in the clonidine group during intubation. During extubation, MAP was lower in the clonidine group. CO and MAP increased less as compared with baseline measurements in the clonidine group. Compared with the measurements after surgery CO less in the clonidine group during extubation (p < 0.05 for all results).

CONCLUSIONS

A single preoperative IV dose of clonidine (3 microg/kg) blunts the hemodynamic responses due to extubation in noncardiac surgery of intermediate duration.

A new model for the assessment of lung allograft ischemia/reperfusion injury

Lung edema is the main clinical manifestation of reperfusion injury following lung transplantation. The evaluation of strategies to prevent this injury is of high clinical importance. Therefore we developed a large-animal model to study the mechanisms of ischemia/reperfusion injury including dynamics of posttransplant reperfusion edema and their prevention. Left lung allotransplantation was performed in 6 weight-matched pigs (25-31 kg). Donor lungs were flushed with 1.5 L low-potassium dextran (LPD) solution (4 degrees C) and preserved for 20 h at 1 degrees C. One hour after reperfusion the recipient contralateral right lung was excluded from perfusion and ventilation to assess graft function only. Extravascular lung water index (EVLWI), intrathoracic blood volume (ITBV), and cardiac output (CO) were assessed (q = 30 min) with a lung water computer (Cold Z-021, Partig, Munich, Germany) by the thermo-dye technique during a 5-h observation period. Gas exchange (FIO2 = 1.0) was measured hourly, and hemodynamics were monitored continuously. The EVLWI of the recipient contralateral lung together with the donor left lung at the time of reperfusion was 6.5+/-1.1 ml/kg, increasing to 7.1+/-1.0 ml/kg at 60 min after reperfusion. After occlusion of the recipient right lung, EVLWI in the graft further increased within 80 min from 8.1+/-0.5 ml/kg to a peak of 11.4+/-1.3 ml/kg, followed by a decrease to 8.5+/-0.8 ml/kg at 5 h after reperfusion in 5 of 6 animals. In 1 animal a severe alveolar edema developed with subsequent deterioration of gas exchange and death 4.5 h after reperfusion. In this animal, peak EVLWI reached 16.8 ml/kg, PaO2 deteriorated from 60.1 to 7.8 kPa, and CO decreased from 3.1 to 1.4 L/min. In all other animals, ITBV (515+/-51 ml), left atrial pressure (LAP), central venous pressure (CVP), and CO (2.9+/-0.3 L/min) were stable during the 5-h assessment period. We conclude that EVLWI measurement is a reliable and very sensitive method to quantify lung allograft reperfusion edema. It may prove useful in early assessment of lung allograft reperfusion injury in the clinical setting and in experimental models.

The nitric oxide synthase cofactor tetrahydrobiopterin reduces allograft ischemia-reperfusion injury after lung transplantation

OBJECTIVE

Exogenous nitric oxide reduces ischemia-reperfusion injury after solid organ transplantation. Tetrahydrobiopterin, an essential cofactor for nitric oxide synthases, may restore impaired endothelium-dependent nitric oxide synthesis. We evaluated whether tetrahydrobiopterin administration to the recipient attenuates lung reperfusion injury after transplantation in swine.

METHODS

Unilateral left lung transplantation was performed in 15 weight-matched pigs (24-31 kg). Donor lungs were flushed with 1.5 L cold (1 degrees C) low-potassium-dextran solution and preserved for 20 hours. Group I animals served as controls. Group II and III animals were treated with a bolus of tetrahydrobiopterin (20 mg/kg). In addition, in group III a continuous infusion of tetrahydrobiopterin (10 mg/kg per hour over 5 hours) was given. One hour after reperfusion, the recipient right lung was occluded. Cyclic guanosine monophosphate levels were measured in the pulmonary venous and central venous blood. Extravascular lung water index, hemodynamic variables, lipid peroxidation, and neutrophil migration to the allograft were assessed.

RESULTS

In group III a significant reduction of extravascular lung water was noted in comparison with the controls (P =.0047). Lipid peroxidation in lung allograft tissue was significantly reduced in group II (P =.0021) and group III ( P =. 0077) in comparison with group I. Pulmonary venous levels of cyclic guanosine monophosphate increased up to 23 +/- 1 pmol/mL at 5 hours in group II and up to 40 +/- 1 pmol/mL in group III (group I, 4.1 +/- 0.5 pmol/mL [I vs III]; P <.001), whereas central venous levels of cyclic guanosine monophosphate were unchanged in all groups.

CONCLUSION

Tetrahydrobiopterin administration during lung allograft reperfusion may reduce posttransplantation lung edema and oxygen-derived free radical injury in the graft. This effect is mediated by local enhancement of the nitric oxide/cyclic guanosine monophosphate pathway.